405P/Lemmon
| Parameter |
Value |
| Designation |
405P/Lemmon |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-12-24T14:12:20.220480Z |
| Orbit solution date (soln_date, UTC) |
2021-05-31T22:43:11Z |
| Obs used |
1017 |
| NEO |
Yes |
| M1 |
18.800 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-10-17T03:08:48.076800Z |
| Discovery magnitude (MPC) |
18.80 G |
| Discovery observatory (MPC) |
Z84 · Calar Alto-Schmidt |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-12-04.0000000 |
| e |
0.68914700 |
| q (au) |
1.121217 |
| a (au) |
3.606904 |
| i (deg) |
9.365069 |
| Ω (om, deg) |
3.311168 |
| ω (w, deg) |
112.292821 |
| M (ma, deg) |
199.344113 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.090 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.090 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
2.314 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2020-06-28 |
2020-12-24 |
-1.5360 |
-0.178 |
| 2020-12-24 |
2021-03-05 |
+6.7770 |
-0.321 |
| 2021-03-05 |
2021-05-10 |
-7.1641 |
+1.615 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
21:37:34.53 |
-19:42:24.3 |
HIP 106723 |
16.05 |
| 2026-02-03 12:00 |
21:37:59.58 |
-19:40:07.7 |
HIP 106876 |
12.27 |
| 2026-02-04 00:00 |
21:38:24.66 |
-19:37:51.1 |
HIP 106876 |
6.10 |
| 2026-02-04 12:00 |
21:38:49.75 |
-19:35:34.3 |
HIP 106876 |
1.96 |
| 2026-02-05 00:00 |
21:39:14.87 |
-19:33:17.3 |
HIP 106876 |
7.13 |
| 2026-02-05 12:00 |
21:39:40.00 |
-19:31:00.3 |
HIP 106876 |
13.35 |
| 2026-02-06 00:00 |
21:40:05.15 |
-19:28:43.1 |
HIP 106876 |
19.66 |
| 2026-02-06 12:00 |
21:40:30.31 |
-19:26:25.9 |
HIP 106876 |
26.00 |
| 2026-02-07 00:00 |
21:40:55.50 |
-19:24:08.5 |
HIP 107111 |
26.99 |
| 2026-02-07 12:00 |
21:41:20.69 |
-19:21:51.0 |
HIP 107111 |
27.19 |
| 2026-02-08 00:00 |
21:41:45.90 |
-19:19:33.4 |
HIP 107238 |
27.19 |
| 2026-02-08 12:00 |
21:42:11.13 |
-19:17:15.7 |
HIP 107238 |
24.81 |
| 2026-02-09 00:00 |
21:42:36.37 |
-19:14:57.9 |
HIP 107188 |
23.00 |
| 2026-02-09 12:00 |
21:43:01.62 |
-19:12:40.1 |
HIP 107188 |
21.34 |
| 2026-02-10 00:00 |
21:43:26.89 |
-19:10:22.1 |
HIP 107188 |
21.54 |
| 2026-02-10 12:00 |
21:43:52.16 |
-19:08:04.0 |
HIP 107304 |
22.56 |
| 2026-02-11 00:00 |
21:44:17.45 |
-19:05:45.9 |
HIP 107304 |
25.04 |
| 2026-02-11 12:00 |
21:44:42.75 |
-19:03:27.6 |
HIP 107312 |
26.96 |
| 2026-02-12 00:00 |
21:45:08.05 |
-19:01:09.3 |
HIP 107312 |
27.29 |
| 2026-02-12 12:00 |
21:45:33.37 |
-18:58:50.9 |
HIP 107312 |
29.07 |
| 2026-02-13 00:00 |
21:45:58.69 |
-18:56:32.5 |
HIP 107603 |
25.21 |
| 2026-02-13 12:00 |
21:46:24.02 |
-18:54:13.9 |
HIP 107603 |
18.82 |
| 2026-02-14 00:00 |
21:46:49.35 |
-18:51:55.4 |
HIP 107603 |
12.46 |
| 2026-02-14 12:00 |
21:47:14.70 |
-18:49:36.7 |
HIP 107603 |
6.23 |
| 2026-02-15 00:00 |
21:47:40.04 |
-18:47:18.0 |
HIP 107603 |
2.21 |
| 2026-02-15 12:00 |
21:48:05.39 |
-18:44:59.3 |
HIP 107603 |
7.32 |
| 2026-02-16 00:00 |
21:48:30.75 |
-18:42:40.5 |
HIP 107603 |
13.60 |
| 2026-02-16 12:00 |
21:48:56.10 |
-18:40:21.6 |
HIP 107771 |
15.05 |
| 2026-02-17 00:00 |
21:49:21.46 |
-18:38:02.7 |
HIP 107771 |
9.82 |
| 2026-02-17 12:00 |
21:49:46.82 |
-18:35:43.8 |
HIP 107771 |
7.00 |
| 2026-02-18 00:00 |
21:50:12.18 |
-18:33:24.8 |
HIP 107771 |
9.19 |
| 2026-02-18 12:00 |
21:50:37.54 |
-18:31:05.9 |
HIP 107771 |
14.25 |
| 2026-02-19 00:00 |
21:51:02.90 |
-18:28:46.9 |
HIP 107901 |
12.57 |
| 2026-02-19 12:00 |
21:51:28.25 |
-18:26:27.8 |
HIP 107901 |
11.35 |
| 2026-02-20 00:00 |
21:51:53.60 |
-18:24:08.8 |
HIP 107901 |
13.52 |
| 2026-02-20 12:00 |
21:52:18.95 |
-18:21:49.8 |
HIP 107901 |
17.88 |
| 2026-02-21 00:00 |
21:52:44.30 |
-18:19:30.7 |
HIP 107901 |
23.22 |
| 2026-02-21 12:00 |
21:53:09.64 |
-18:17:11.7 |
HIP 107901 |
29.02 |
| 2026-02-22 00:00 |
21:53:34.97 |
-18:14:52.6 |
HIP 108214 |
25.42 |
| 2026-02-22 12:00 |
21:54:00.30 |
-18:12:33.6 |
HIP 108214 |
19.49 |
| 2026-02-23 00:00 |
21:54:25.62 |
-18:10:14.5 |
HIP 108214 |
14.03 |
| 2026-02-23 12:00 |
21:54:50.93 |
-18:07:55.5 |
HIP 108214 |
9.82 |
| 2026-02-24 00:00 |
21:55:16.24 |
-18:05:36.5 |
HIP 108214 |
8.89 |